Stereo Signal Delay Alignment for Accurate ITD Decoding
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Solution Overview
Problem
Existing time-domain stereo encoding and decoding technologies result in deviations between the inter-channel time difference of the decoded stereo signal and the original stereo signal due to encoding and decoding delays, affecting the accuracy of the stereo sound image.
Innovation Solution
Perform interpolation processing on the inter-channel time difference in the current frame and the previous frame to adjust and encode the time difference, ensuring it matches the decoded primary and secondary-channel signals, thereby reducing deviations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If time-domain stereo encoding and decoding is performed with encoding and decoding delays, then the stereo signal can be compressed and transmitted, but the inter-channel time difference of the decoded signal deviates from the original signal
Solution Approach 1:
The patent applies preliminary action by performing delay alignment on the stereo signal before time-domain downmixing processing. The encoder estimates the inter-channel time difference and applies delay alignment to compensate for encoding/decoding delays in advance, so that when the signal is decoded, the inter-channel time difference matches the original signal's characteristics, resolving the deviation problem while maintaining compression efficiency
2Measurement precision
If delay alignment is performed on the stereo signal, then the inter-channel time difference can be compensated, but additional processing time and complexity are introduced
Solution Approach 1:
The patent applies parameter changes by modifying the delay alignment process to operate on the time-domain signal parameters directly. Instead of complex multi-stage processing, the system adjusts the delay alignment based on estimated inter-channel time difference parameters and applies compensation factors that simplify the overall processing complexity while maintaining accuracy in restoring the inter-channel time difference
Data Source
AI summary
This disclosure provides an encoding method, and an encoder for a multi-channel signal. The encoding method includes: obtaining a first ITD of a current frame of a multi-channel signal includes an initial left channel signal and an initial right channel signal; obtaining a second ITD of the current frame based on the first ITD and a third ITD of a previous frame of the multi-channel signal; performing delay alignment on the left channel signal and the right channel signal based on the second ITD, to obtain a aligned left channel signal and a aligned right channel signal; and encoding the aligned left channel signal and the aligned right channel signal.